The present disclosure relates to a battery pack that includes a battery having at least one rechargeable battery and that performs charge from a charger to the battery and power supply (discharge) from the battery to a motor-driven appliance.
As disclosed in Published Japanese Patent No. 5281843, for example, a battery pack that is attached to a motor-driven appliance, such as a power tool and a motor-driven operating machine, and that supplies power thereto includes a battery having at least one rechargeable battery; a control circuit that monitors a battery voltage, a current flowing to the battery during charge to the battery, and a current flowing from the battery during discharge of the battery, to thereby control charge and discharge of the battery; and a pair of external terminals for electrical connection to an external device (charger or motor-driven appliance).
The battery pack may further include a protection element that inhibits a current from flowing through a current path connecting the battery and the external terminals, when an abnormality occurs in the battery pack.
If a current flows through the current path connecting the battery and the external terminals when the battery pack is abnormal, the protection element cuts off the electrical connection between the battery and the external terminals, and thereby protects the battery and the external device (charger or motor-driven appliance) from being damaged. The protection element may comprise, for example, a fuse, an SCP (self-control protector), or an FET.